Methods for forming a rhenium-containing film on a substrate by a cyclical deposition process and related semiconductor device structures

ABSTRACT

Methods for forming a rhenium-containing film on a substrate by a cyclical deposition are disclosed. The method may include: contacting the substrate with a first vapor phase reactant comprising a rhenium precursor; and contacting the substrate with a second vapor phase reactant. Semiconductor device structures including a rhenium-containing film formed by the methods of the disclosure are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional patent application Ser. No. 16/219,555 filed Dec. 13, 2018 titled METHODS FOR FORMING A RHENIUM-CONTAINING FILM ON A SUBSTRATE BY A CYCLICAL DEPOSITION PROCESS AND RELATED SEMICONDUCTOR DEVICE STRUCTURES, the disclosure of which is hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The present disclosure relates generally to methods for forming a rhenium-containing film on a substrate by a cyclical deposition process and particularly methods for forming a rhenium-containing film by a cyclical deposition process utilizing a rhenium precursor.

BACKGROUND OF THE DISCLOSURE

Rhenium-containing films may be utilized in a wide variety of technology applications. For example, elemental rhenium films may be used as a catalyst, in high-temperature superalloys, in superconducting applications, in adhesion layers, in liners, in diffusion barriers, in seed layers to improve growth of other materials, and in microelectronic applications. In addition, rhenium oxides may exhibit a low electrical resistivity and therefore may be utilized as electrodes to semiconductor device structures, such as, for example, a dynamic random-access memory (DRAM) device. Furthermore, rhenium sulfides, such as, for example, rhenium disulfide (ReS₂), have been shown to behave in a manner similar to 2D materials, even in 3D bulk form. Therefore, rhenium sulfides may find applications in tribology, other low-frication applications, solar cell applications, quantum computing, and ultrafast data processing. Accordingly, methods for forming rhenium-containing films and related semiconductor device structures including rhenium-containing films are highly desirable.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in a simplified form. These concepts are described in further detail in the detailed description of example embodiments of the disclosure below. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

In some embodiments, methods for forming a rhenium-containing film on a substrate by a cyclical deposition process are provided. The methods may comprise: contacting the substrate with a first vapor phase reactant comprising a rhenium precursor selected from the group comprising: a rhenium oxyhalide precursor, an alkyl rhenium oxide precursor, a cyclopentadienyl based rhenium precursor, or a rhenium carbonyl halide precursor; and contacting the substrate with a second vapor phase reactant.

For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described herein above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught or suggested herein without necessarily achieving other objects or advantages as may be taught or suggested herein.

All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description of certain embodiments having reference to the attached figures, the invention not being limited to any particular embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

While the specification concludes with claims particularly pointing out and distinctly claiming what are regarded as embodiments of the invention, the advantages of embodiments of the disclosure may be more readily ascertained from the description of certain examples of the embodiments of the disclosure when read in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a non-limiting exemplary process flow, demonstrating a method for forming a rhenium oxide film on a substrate by a cyclical deposition process according to the embodiments of the disclosure;

FIG. 2 illustrates a non-limiting exemplary process flow, demonstrating an additional method for forming a rhenium oxide film on a substrate by a cyclical deposition process according to the embodiments of the disclosure;

FIG. 3 illustrates a non-limiting exemplary process flow, demonstrating a further method for forming a rhenium oxide film on a substrate by a cyclical deposition process according to the embodiments of the disclosure;

FIGS. 4A-4C illustrate cross-sectional schematic diagrams of semiconductor structures that may be formed by a process for forming a low resistivity rhenium oxide film on a substrate by a cyclical deposition process according to the embodiments of the disclosure;

FIG. 5 illustrates a non-limiting exemplary process flow, demonstrating a method for forming a rhenium sulfide film on a substrate by a cyclical deposition process according to the embodiments of the disclosure;

FIG. 6 illustrates a non-limiting exemplary process flow, demonstrating an additional method for forming a rhenium sulfide film on a substrate by a cyclical deposition process according to the embodiments of the disclosure;

FIG. 7 illustrates a non-limiting exemplary process flow, demonstrating a method for forming an elemental rhenium film on a substrate by a cyclical deposition process according to the embodiments of the disclosure;

FIG. 8 illustrates a non-limiting exemplary process flow, demonstrating an additional method for forming an elemental rhenium film on a substrate by a cyclical deposition process according to the embodiments of the disclosure;

FIG. 9 illustrates a cross-sectional schematic diagram of a semiconductor device structure including a rhenium-containing film formed according to the embodiments of the disclosure; and

FIG. 10 illustrates an exemplary reaction system configured for performing the cyclical deposition methods according to the embodiments of the disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it will be understood by those in the art that the invention extends beyond the specifically disclosed embodiments and/or uses of the invention and obvious modifications and equivalents thereof. Thus, it is intended that the scope of the invention disclosed should not be limited by the particular disclosed embodiments described below.

The illustrations presented herein are not meant to be actual views of any particular material, structure, or device, but are merely idealized representations that are used to describe embodiments of the disclosure.

As used herein, the term “rhenium oxyhalide precursor” may refer to a molecule having the general formula Re_(a)O_(b)X_(c) wherein Re is rhenium, O is oxygen, X is a halogen atom, such as, for example, fluorine (F), chlorine (Cl), bromine (Br), or iodine (I), and a, b, and c, are integers equal to 1 or greater.

As used herein, the term “cyclical chemical vapor deposition” may refer to any process wherein a substrate is sequentially exposed to two or more volatile precursors, which react and/or decompose on a substrate to produce a desired deposition.

As used herein, the term “substrate” may refer to any underlying material or materials that may be used, or upon which, a device, a circuit, or a film may be formed.

As used herein, the term “atomic layer deposition” (ALD) may refer to a vapor deposition process in which deposition cycles, including a plurality of consecutive deposition cycles, are conducted in a reaction chamber. Typically, during each cycle the precursor is chemisorbed to a deposition surface (e.g., a substrate surface or a previously deposited underlying surface such as material from a previous ALD cycle), forming a monolayer or sub-monolayer that does not readily react with additional precursor (i.e., a self-limiting reaction). Thereafter, if necessary, a reactant (e.g., another precursor or reaction gas) may subsequently be introduced into the process chamber for use in converting the chemisorbed precursor to the desired material on the deposition surface. Typically, this reactant is capable of further reaction with the precursor. Further, purging steps may also be utilized during each cycle to remove excess precursor from the process chamber and/or remove excess reactant and/or reaction byproducts from the process chamber after conversion of the chemisorbed precursor. Further, the term “atomic layer deposition,” as used herein, is also meant to include processes designated by related terms such as, “chemical vapor atomic layer deposition”, “atomic layer epitaxy” (ALE), molecular beam epitaxy (MBE), gas source MBE, or organometallic MBE, and chemical beam epitaxy when performed with alternating pulses of precursor composition(s), reactive gas, and purge (e.g., inert carrier) gas.

As used herein, the term “film” and “thin film” may refer to any continuous or non-continuous structures and material formed by the methods disclosed herein. For example, “film” and “thin film” could include 2D materials, nanorods, nanolaminates, nanotubes, or nanoparticles or even partial or full molecular layers or partial or full atomic layers or clusters of atoms and/or molecules. “Film” and “thin film” may comprise material or a layer with pinholes, but still be at least partially continuous.

A number of example materials are given throughout the embodiments of the current disclosure, it should be noted that the chemical formulas given for each of the example materials should not be construed as limiting and that the non-limiting example materials given should not be limited by a given example stoichiometry.

The present disclosure includes methods and related semiconductor device structures that may be used to form and may utilize rhenium-containing films. Such rhenium containing films, such as, for example, elemental rhenium films, rhenium oxide films, rhenium sulfide films, and rhenium boride films, may be utilized in a wide variety of technology applications.

As a non-limiting example, certain rhenium oxide films, such as, for example, rhenium trioxide (ReO₃), may exhibit very low electrical resistivity and may therefore be exploited in a number of semiconductor device applications, including, but not limited to, device interconnects, barrier layers, Schottky devices, metal-insulator-semiconductor (MIS) devices, metal-insulator-metal devices (MIM), and as a portion of a gate electrode.

Rhenium oxides may be also utilized in the doping of semiconductor devices. For example, rhenium oxides may be utilized to modulate the conductivity of semiconductor materials as well as to adjust the adhesion of certain materials. In additional examples, rhenium oxides may be utilized to form interesting mixed compounds, such as, in case of solid-solid reactions, for example.

Due to the attractive physical properties of rhenium oxides, such as, for example, rhenium dioxide, rhenium trioxide, or di-rhenium hepta-oxide, several new applications can be exploited. In some embodiments, rhenium oxides may be utilized for bottom up filling or filling of trench structures, pits, or gap structures, in complex 3D structures. The bottom-up and/or gap filling by a rhenium oxide can be realized in many ways, such as, but not limited to, depositing rhenium oxide at low deposition temperatures and subsequently annealing the deposited rhenium oxide film at a higher temperature to reflow the rhenium oxide film into the lower regions of a 3D structure. The annealing temperature of the rhenium oxide film may be greater than 50° C., or greater than 100° C., or greater than 200° C., or greater than 300° C., or even greater than 350° C. The annealing of the rhenium oxide film may be carried out in an oxidative or a reductive environment in order to maintain a specific composition of the rhenium oxide film. For example, annealing of the rhenium oxide film may be performed in an environment comprising at least one of nitrogen monoxide (NO), nitrogen dioxide (NO₂), a sulfur oxide (e.g., SO₂ or SO₃), oxygen, or water.

As a further non-limiting example, a rhenium oxide, such as, Re₂O₇ may be utilized as a source material for a chemical vapor deposition (CVD) process, wherein Re₂O₇ may begin to sublime above a temperature of approximately 100° C., or above a temperature of approximately 150° C., or even above a temperature of approximately 180° C., in order to deposit Re₂O₇ for thin film applications and/or gap fill applications.

In some embodiments of the disclosure, the deposition temperature may be carefully controlled such that a first composition of a rhenium oxide film may be deposited over a second composition of a rhenium oxide film, wherein the first composition and the second composition are different from one another. For example, at a deposition temperature between approximately 220° C. and 350° C. a rhenium oxide film not comprising the composition Re₂O₇ may be deposited.

In some embodiments, the rhenium oxide films may be deposited over a template structure, such as, for example, corrugated surfaces, and/or patterned surfaces, for the formation of quantum dots, nanodots, nanowires, or nano-patterns, comprising a rhenium oxide material. In such embodiments, the initial material or the final material may be either one of a rhenium oxide, an elemental rhenium metal, a rhenium boride, or a rhenium sulfide. Depending upon the desired rhenium-containing material, various processing steps, such as, for example, oxidation, reduction, or sulfidization, of the initial rhenium-containing film may be utilized. An annealing step, as described above, may also be utilized to enable the rhenium-containing material to accumulate at the lower vertices of the corrugations or lower regions of a 3D structure.

In some embodiments, the deposited rhenium-containing films, or their alloys, may contain either boron, sulfur, carbon, nitrogen, phosphorus, or a combination thereof. In some embodiments, rhenium-containing films are categorized as one of the possible phases of rhenium carbides, rhenium borides, rhenium nitrides, rhenium phosphides, or in some cases may contain more than two elements. For example, rhenium-containing films may comprise boron and carbon, nitrogen and boron, or a possible combination of either boron, carbon, nitrogen, and phosphorus. In some embodiments of the disclosure, the rhenium-containing film may comprise a rhenium boron carbide (ReBC), a rhenium diboride (ReB₂), a dirhenium triboride (Re₂B₃), or a rhenium boride (ReB, Re₃B₇, Re₃B and Re₂B).

In some embodiments of the disclosure, the rhenium-containing films may comprise boron, carbon, nitrogen, sulfur, phosphorus, or any possible combination thereof. The non-limiting applications of such mixed alloys of rhenium, boron, carbon, nitrogen, or phosphorus, may be utilized as adhesion improving layers, seed layers, diffusion barriers, hard coatings, high bulk modulus super hard layers, or liners.

In some embodiments, the rhenium-containing film may comprise at least one of ReBC, ReB, ReC, Re₃P₄, Re₂P, ReP₄, Re₃N, Re₂N, ReN, ReN₂, ReN₄, Re₂C, ReC, Re₄C, ReB₂. In some embodiments, the rhenium-containing films may be used as: superconducting layers, hard masks in patterning applications, etch stop layers in patterning applications, coatings for the reaction chamber as well as its components in either deposition as well as etch reactors, protective coatings against etching chemistries, and ReP₄ as semiconducting layers.

In some cases, it is desirable to form air-gaps and low boiling point rhenium oxide films may be exploited in such applications. For example, annealing a rhenium oxide film above a temperature of approximately 400° C. may sublime a rhenium oxide film completely from a filled gap feature or sublime a deposited rhenium oxide film. In some embodiments, the sublimation of the rhenium oxide film may leave behind a void or alternatively the rhenium oxide film may be utilized as a sacrificial layer and/or as a patterning layer in patterning applications.

In some embodiments, a rhenium-containing film may be utilized in back-end-of-line (BEOL) applications, such as a metal contact, wherein the metal contact may be deposited on top of an underlying liner layer, adhesion layer, seed layer, or diffusion barrier layer, and in some applications the metal contact may be capped by a metal alloy. For example, in some applications the metal interconnect may be elemental rhenium and may be deposited on top of an underlying rhenium alloy, such as, for example, a rhenium carbide, a rhenium boride, a rhenium nitride, or a rhenium phosphide. In some embodiments, the metal precursor utilized to deposit the metal contact is same as that utilized in the deposition of a liner layer, an adhesion layer, a seed layer, or a diffusion barrier layer, and only the choice of the second reactant and/or process conditions (e.g., deposition temperature) may be different. This approach may be advantageous in processing as only one metal precursor is used and this approach can be applied to other processes that utilize different materials, such as, for example, cobalt as the metal contact or interconnect, and cobalt phosphide as an adhesion layer, or a liner layer. Similar approaches can be utilized for ruthenium-based processes and its related carbides.

In addition, certain rhenium oxide films, such as, for example, rhenium (VII) oxide (Re₂O₇), may exhibit dielectric properties and therefore may be utilized in DRAM devices, and as capacitor structures. ReO₂ may find applications in spintronic devices as well as memory devices, such as, Resistive RAM, for example. In some embodiments, the rhenium oxides may be utilized in catalysis sciences. In some embodiments, the deposited rhenium-containing films may promote selective deposition or etching. For example, the catalytic effect of ReO_(x) may assist several ALD precursors to react or decompose on its surface.

Furthermore, certain rhenium oxide films, such as, for example, rhenium trioxide (ReO₃) may exhibit a low melting point and the low metaling point may be taken advantage of by capping the rhenium oxide film with a capping layer, such as, for example, titanium nitride (TiN), and subsequently thermally annealing the rhenium oxide film to either form a single crystal rhenium oxide film or increase the crystal grain sizes of the crystallites comprising the rhenium oxide film thereby decreasing the electrical resistivity of the rhenium oxide film.

Therefore, the embodiments of the disclosure may comprise methods for forming a rhenium-containing film on a substrate by a cyclical deposition process. In some embodiments, the method may comprise: contacting the substrate with a first vapor phase reactant comprising a rhenium precursor selected from the group comprising: a rhenium oxyhalide precursor, an alkyl rhenium oxide precursor, a cyclopentadienyl based rhenium precursor, or a rhenium carbonyl halide precursor; and contacting the substrate with a second vapor phase reactant.

The methods of formation of rhenium-containing films disclosed herein may comprise a cyclical deposition process, such as, for example, atomic layer deposition (ALD), or cyclical chemical vapor deposition (CCVD).

A non-limiting example embodiment of a cyclical deposition process may include atomic layer deposition (ALD), wherein ALD is based on typically self-limiting reactions, whereby sequential and alternating pulses of reactants are used to deposit about one atomic (or molecular) monolayer of material per deposition cycle. The deposition conditions and precursors are typically selected to provide self-saturating reactions, such that an absorbed layer of one reactant leaves a surface termination that is non-reactive with the gas phase reactants of the same reactants. The substrate is subsequently contacted with a different reactant that reacts with the previous termination to enable continued deposition. Thus, each cycle of alternated pulses typically leaves no more than about one monolayer of the desired material. However, as mentioned above, the skilled artisan will recognize that in one or more ALD cycles more than one monolayer of material may be deposited, for example, if some gas phase reactions occur despite the alternating nature of the process.

In an ALD-type process utilized for the formation of a rhenium-containing film, such as, for example, an elemental rhenium film, a rhenium oxide film, a rhenium sulfide film, or a rhenium boride film, one deposition cycle may comprise exposing the substrate to a first vapor phase reactant, removing any unreacted first reactant and reaction byproducts from the reaction chamber, and exposing the substrate to a second vapor phase reactant, followed by a second removal step. In some embodiments of the disclosure, the first vapor phase reactant may comprise a rhenium precursor and the second vapor phase reactant may comprise at least one of an oxygen containing precursor, a sulfur containing precursor, a boron containing precursor, or a hydrogen containing precursor.

In some embodiments of the disclosure, a boron containing precursor may comprise boranes of general formula B_(n)H_(n+x) where n and x are integers greater than or equal to 1. In some embodiments, a boron containing precursor may comprise alkyl borates of general formula R¹R²R³O₃B, where R is any alkyl or aryl group. In some embodiments, a boron containing precursor may comprise at least one of boron hydride (BH₃), diborane (B₂H₆), decaborane (B₁₀H₁₄), tetraborane (B₄H₁₀), trimethylborate, or triethylborate.

Precursors may be separated by inert gases, such as argon (Ar) or nitrogen (N₂), to prevent gas-phase reactions between reactants and enable self-saturating surface reactions. In some embodiments, however, the substrate may be moved to separately contact a first vapor phase reactant and a second vapor phase reactant. Because the reactions self-saturate, strict temperature control of the substrates and precise dosage control of the precursors may not be required. However, the substrate temperature is such that an incident gas species does not condense into monolayers nor decompose on the surface. Surplus chemicals and reaction byproducts, if any, are removed from the substrate surface, such as by purging the reaction space or by moving the substrate, before the substrate is contacted with the next reactive chemical. Undesired gaseous molecules can be effectively expelled from a reaction space with the help of an inert purging gas. A vacuum pump may be used to assist in the purging.

Reactors capable of being used to deposit rhenium-containing films can be used for the cyclical deposition processes described herein. Such reactors include ALD reactors, as well as CVD reactors, configured to provide the precursors. According to some embodiments, a showerhead reactor may be used. According to some embodiments, cross-flow, batch, minibatch, or spatial ALD reactors may be used.

In some embodiments of the disclosure, a batch reactor may be used. In some embodiments, a vertical batch reactor may be used. In other embodiments, a batch reactor comprises a minibatch reactor configured to accommodate 10 or fewer wafers, 8 or fewer wafers, 6 or fewer wafers, 4 or fewer wafers, or 2 or fewer wafers. In some embodiments in which a batch reactor is used, wafer-to-wafer non-uniformity is less than 5% (1 sigma), or less than 3%, or less than 2%, or less than 1%, or even less than 0.5%.

The exemplary cyclical deposition processes described herein may optionally be carried out in a reactor or reaction chamber connected to a cluster tool. In a cluster tool, because each reaction chamber is dedicated to one type of process, the temperature of the reaction chamber in each module can be kept constant, which improves the throughput compared to a reactor in which the substrate is heated up to the process temperature before each run. Additionally, in a cluster tool it is possible to reduce the time to pump the reaction chamber to the desired process pressure levels between substrates. In some embodiments of the disclosure, the exemplary cyclical deposition processes for the formation of rhenium-containing films disclosed herein may be performed in a cluster tool comprising multiple reaction chambers, wherein each individual reaction chamber may be utilized to expose the substrate to an individual precursor gas and the substrate may be transferred between different reaction chambers for exposure to multiple precursors gases, the transfer of the substrate being performed under a controlled ambient to prevent oxidation/contamination of the substrate. In some embodiments of the disclosure, the cyclical deposition processes for the formation of rhenium-containing films may be performed in a cluster tool comprising multiple reaction chambers, wherein each individual reaction chamber may be configured to heat the substrate to a different temperature.

A stand-alone reactor may be equipped with a load-lock. In that case, it is not necessary to cool down the reaction chamber between each run.

In some embodiments, a deposition process utilized in the formation of a rhenium-containing film may comprise a plurality of deposition cycles, for example ALD cycles or cyclical CVD cycles.

In some embodiments the cyclical deposition process may be a hybrid ALD/CVD or a cyclical CVD process. For example, in some embodiments, the growth rate of the ALD process may be low compared with a CVD process. One approach to increase the growth rate may be that of operating at a higher substrate temperature than that typically employed in an ALD process, resulting in some portion of a chemical vapor deposition process, but still taking advantage of the sequential introduction of precursors, such a process may be referred to as cyclical CVD. In some embodiments, a cyclical CVD process may comprise the introduction of two or more precursors into the reaction chamber wherein there may be a time period of overlap between the two or more precursors in the reaction chamber resulting in both an ALD component of the deposition and a CVD component of the deposition. For example, a cyclical CVD process may comprise the continuous flow of a first precursor and the periodic pulsing of a second precursor into the reaction chamber.

According to some embodiments of the disclosure, ALD processes may be used to form a rhenium-containing film on a substrate, such as an integrated circuit work piece. In some embodiments, of the disclosure, each ALD cycle may comprise two or more distinct deposition steps or stages. In a first stage of the deposition cycle (“the rhenium stage”), the substrate surface on which deposition is desired may be contacted with a first vapor phase reactant comprising a rhenium precursor which chemisorbs on to the surface of the substrate, forming no more than about one monolayer of reactant species on the surface of the substrate. In a second stage of the deposition the substrate surface on which deposition is desired may be contacted with a second vapor phase reactant comprising at least one of an oxygen containing precursor, a sulfur containing precursor, a boron containing precursor, or a hydrogen containing precursor. Additional stages may comprise, an oxidation stage, a reduction stage, and/or a pre-cleaning stage.

In some embodiment of the disclosure, a specific oxide of rhenium may be selectively deposited over the surface of another composition of rhenium oxide. Such selective oxidation can be controlled by specifically choosing the oxidative environment. In some embodiments, a certain oxidative environment may be periodically applied to the cyclical deposition process.

In some embodiments of the disclosure, a reduction stage may be applied to the cyclical deposition process. In such embodiments, the reduction stage may be necessary to maintain a specific oxidation state of the rhenium in the rhenium-containing film, wherein the rhenium-containing film may contain, but is not limited to, rhenium, oxygen, carbon, hydrogen, nitrogen, a halide, phosphorus, sulfur, or boron.

Exemplary Cyclical Deposition Processes for the Formation of Rhenium Oxide Films

In some embodiments of disclosure, a cyclical deposition process may be utilized to form a rhenium oxide, such as, for example, at least one of rhenium (IV) oxide (ReO₂), rhenium trioxide (ReO₃), rhenium (VII) oxide (Re₂O₇), or a rhenium oxide having the general formula Re_(a)O_(b), wherein a and b have a value less than 7. In some embodiments, the rhenium oxide may comprise a sub-oxide with the general formula ReO_(x) wherein x may be less than 2.

In some embodiments, the cyclical deposition process may comprise forming the rhenium oxide film by the surface reaction between a first vapor phase reactant and a second vapor phase reactant. In some embodiments, the cyclical deposition process may comprise forming an intermediate rhenium oxide film followed by contacting the intermediate rhenium oxide film with a reducing agent precursor to form a rhenium oxide film of the desired composition. In some embodiments, the cyclical deposition process may comprise forming an intermediate rhenium oxide film followed by contacting the intermediate rhenium oxide film with an additional oxygen containing precursor to form a rhenium oxide film of the desired composition.

An exemplary rhenium oxide film formation process may be understood with reference to FIG. 1 which illustrates an exemplary cyclical deposition process 100 for the formation of a rhenium oxide film.

In more detail, FIG. 1 illustrates an exemplary rhenium oxide formation process 100 including a cyclical deposition phase 105. The exemplary rhenium oxide formation process 100 may commence with a process block 110 which comprises, providing a substrate into a reaction chamber and heating the substrate to a desired deposition temperature.

In some embodiments of the disclosure, the substrate may comprise a planar substrate or a patterned substrate including high aspect ratio features, such as, for example, trench structures and/or fin structures. The substrate may comprise one or more materials including, but not limited to, silicon (Si), germanium (Ge), germanium tin (GeSn), silicon germanium (SiGe), silicon germanium tin (SiGeSn), silicon carbide (SiC), or a group III-V semiconductor material, such as, for example, gallium arsenide (GaAs), gallium phosphide (GaP), or gallium nitride (GaN). In some embodiments of the disclosure, the substrate may comprise an engineered substrate wherein a surface semiconductor layer is disposed over a bulk support with an intervening buried oxide (BOX) disposed there between. In some embodiments liners may be used and may comprise for example metals, metal nitrides, metal borides, metal carbides, metal phosphides, or metal sulfides. In some embodiments, the liner may comprise at least one of titanium nitride, tantalum nitride, tantalum carbide, tungsten carbide, molybdenum, niobium boride, or niobium carbide.

Patterned substrates may comprise substrates that may include semiconductor device structures formed into or onto a surface of the substrate, for example, a patterned substrate may comprise partially fabricated semiconductor device structures, such as, for example, transistors and/or memory elements. In some embodiments, the substrate may contain monocrystalline surfaces and/or one or more secondary surfaces that may comprise a non-monocrystalline surface, such as a polycrystalline surface and/or an amorphous surface. Monocrystalline surfaces may comprise, for example, one or more of silicon (Si), silicon germanium (SiGe), germanium tin (GeSn), or germanium (Ge). Polycrystalline or amorphous surfaces may include dielectric materials, such as oxides, oxynitrides or nitrides, such as, for example, silicon oxides and silicon nitrides.

The reaction chamber utilized for the deposition may be an atomic layer deposition reaction chamber, or a chemical vapor deposition reaction chamber, or any of the reaction chambers as previously described herein. In some embodiments of the disclosure, the substrate may be heated to a desired deposition temperature for the subsequent cyclical deposition phase 105. For example, the substrate may be heated to a substrate temperature of less than approximately 750° C., or less than approximately 650° C., or less than approximately 550° C., or less than approximately 450° C., or less than approximately 350° C., or less than approximately 250° C., or even less than approximately 150° C. In some embodiments of the disclosure, the substrate temperature during the cyclical deposition phase may be between 300° C. and 750° C., or between 400° C. and 600° C., or between 400° C. and 450° C. In some embodiments, the substrate temperature during the cyclical deposition phase may be between 80° C. and 150° C., or between 150° C. and 200° C., or even between 200° C. and 350° C.

Upon heating the substrate to a desired deposition temperature, the exemplary rhenium oxide formation process 100 may continue with a cyclical deposition phase 105 by means of a process block 120, which comprises contacting the substrate with a first vapor phase reactant and particularly, in some embodiments, contacting the substrate with a first vapor phase reactant comprising a rhenium vapor phase reactant, i.e., the rhenium precursor.

In some embodiments of the disclosure, the rhenium precursor may comprise a rhenium halide precursor. In some embodiments, the rhenium halide precursor may have an oxidation state of either 4, or 5, or 6, or 7. In some embodiments, the rhenium halide precursor may comprise at least one of a rhenium chloride, a rhenium fluoride, a rhenium bromide, or a rhenium iodide. In some embodiments, the first vapor phase reactant may comprise a rhenium chloride, such as, for example, rhenium hexachloride (ReCl₆), or rhenium pentachloride (ReCl₅). In some embodiments, the first vapor phase reactant may comprise a rhenium bromide, such as, for example, rhenium pentabromide (ReBr₅). In some embodiments, the first vapor phase reactant may comprise a rhenium fluoride, such as, for example, rhenium pentafluoride (ReF₅), rhenium heptafluoride (ReF₇), or rhenium hexafluoride (ReF₆).

In some embodiments of the disclosure, the rhenium precursor may comprise a rhenium oxyhalide precursor, wherein the term “rhenium oxyhalide precursor” may refer to a molecule having the general formula Re_(a)O_(b)X_(c) wherein Re is rhenium, O is oxygen, X is a halogen atom, such as, for example, fluorine (F), chlorine (Cl), bromine (Br), or iodine (I), and a, b, and c, are integers equal to 1 or greater.

In some embodiments, the rhenium oxyhalide may comprise various oxidation states. For example, the oxidation state of the rhenium in the rhenium oxyhalide can be either 2, or 3, or 4, or 5, or 6, or even 7. In some embodiments, the rhenium oxyhalide may comprise one, two, or three neutral ligands. For example, the neutral ligands can be alkyl or aryl amines, alkyl or aryl phosphines, or cyclic amines, such as, pyridine, for example. In some embodiments, the rhenium oxyhalide may comprise, oxotrichloro bis(triphenylphosphine) rhenium(V) ReOCl₃[PPh₃]₂, oxotrichloro bis(trimethylphosphine) rhenium(V) ReOCl₃[(CH₃)₃P]₂, or oxotrichloro bis(dimethylamino) rhenium(V) ReOCl₃[(Me₂NH)]₂. In some embodiments, the rhenium precursor may comprise a rhenium oxyfluoride, including, but not limited to, rhenium oxyfluoride (ReOF), rhenium trioxyfluoride (ReO₃F), rhenium oxytetrafluoride (ReOF₄), rhenium oxypentafluoride (ReOF₅), or rhenium dioxydifluoride (ReO₂F₂). In some embodiments, the rhenium precursor may comprise a rhenium oxychloride, including, but not limited to, rhenium oxychloride (ReOCl), rhenium trioxychloride (ReO₃Cl), or rhenium dioxy dichloride (ReO₂Cl₃).

In some embodiments, the rhenium precursor may comprise an alkyl rhenium oxide, such as, an alkyl rhenium trioxide (RReO₃, wherein R is an alkyl group). In some embodiments, the alkyl rhenium oxide precursor may comprise methyl rhenium trioxide (CH₃ReO₃).

In some embodiments, the rhenium precursor may comprise a cyclopentadienyl based rhenium precursor. In some embodiments, the cyclopentadienyl based rhenium precursor may comprise at least one of a cyclopentadienyl rhenium hydride, a pentacarbonyl hydridorhenium ReH[CO]₅, a cyclopentadienyl rhenium carbonyl, or a dirhenium decacarbonyl Re₂[CO]₁₀. In some embodiments, the cyclopentadienyl rhenium hydride precursor may comprise ReHCp₂. In some embodiments, the cyclopentadienyl rhenium carbonyl may have an oxidation state of either 1, or 2, or 3, or 4, or 5, or 6. For example, the cyclopentadienyl rhenium carbonyl may comprise ReCp[CO]₃, amino cylopentadienylrhenium carbonyl Re(C₅H₄NH₂)(CO)₃, or Re[C₅Me₅][CO]₃.

In some embodiments, the rhenium precursor may comprise a rhenium carbonyl halide precursor having the general formula ReX_(a)[CO]_(b) with an oxidation state of either 1, or 2 or 3, or 4, or 5, or 6, wherein X can be fluorine, bromine, chlorine, or iodine, and ‘a’, ‘b’ can be greater than or equal to 1. In some embodiments, the rhenium carbonyl halide precursor may comprise, chloropentacarbonylrhenium (I) ReCl[CO]₅), or bromopentacarbonylrhenium (I) ReBr[CO]₅.

In some embodiments of the disclosure, the metal precursor may be selected to deposit a metal and metal alloy by the selection of the second reactant and/or by changing the processing conditions. In some embodiments, the second reactant can be a hydrogen or a nitrogen containing precursor, such as, for example, hydrogen gas, ammonia, an alkyl amine, an ammonia-hydrogen mixture, a nitrogen-hydrogen plasma, a hydrogen plasma, or a boron containing precursor, such as, a borane, an alkyl borate, or a carbon containing precursor, such as, for example, an alkyl halide, an organic mixed halide, a saturated or unsaturated as well as aliphatic or non-aliphatic alkane, or a phosphorus containing precursor, such as, for example, phosphine (PH₃), or alkylphosphines.

In some embodiments, an organic mixed halide is of general form C_(a)X_(b)Y_(d), whereas C is carbon, and X, Y are halides such as chlorine or bromine or iodine or fluorine and a, b, d are integers more than 1.

In some embodiments of the disclosure, contacting the substrate with a first vapor phase reactant comprising a rhenium precursor may comprise contacting the rhenium precursor to the substrate for a time period of between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. In addition, during the contacting of the substrate with the rhenium precursor, the flow rate of the rhenium precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. In addition, during the contacting of the rhenium precursor to the substrate the flow rate of the rhenium precursor may range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

The exemplary rhenium oxide formation process 100 of FIG. 1 may continue by purging the reaction chamber. For example, excess first vapor phase reactant and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping with an inert gas. In some embodiments of the disclosure, the purge process may comprise a purge cycle wherein the substrate surface is purged for a time period of less than approximately 5.0 seconds, or less than approximately 3.0 seconds, or even less than approximately 2.0 seconds. Excess first vapor phase reactant, such as, for example, excess rhenium precursor and any possible reaction byproducts may be removed with the aid of a vacuum, generated by a pumping system in fluid communication with the reaction chamber.

Upon purging the reaction chamber with a purge cycle the exemplary rhenium oxide formation process 100 may continue with a second stage of the cyclical deposition phase 105 by means of a process block 130 which comprises, contacting the substrate with a second vapor phase reactant, and particularly contacting the substrate with a second vapor phase reactant comprising an oxygen containing precursor (“the oxygen precursor”).

In some embodiments, the oxygen containing precursor may comprise at least one of oxygen, ozone (O₃), an oxygen plasma, hydrogen peroxide (H₂O₂), water (H₂O), or formic acid. In some embodiments, the rhenium precursor may comprise rhenium oxydifluoride (ReOF₂), or rhenium dioxydichloride (ReOCl₂), and the second vapor phase reactant may comprise water (H₂O), ozone (O₃), or hydrogen peroxide (H₂O₂). In some embodiments, the rhenium precursor may comprise rhenium oxytetrafluoride (ReOF₄), or rhenium oxytetrachloride (ReOCl₄), and the second vapor phase reactant may comprise water (H₂O), ozone (O₃) or hydrogen peroxide (H₂O₂).

In some embodiments of the disclosure, the oxygen containing precursor may comprise at least one of water (H₂O), ozone (O₃), hydrogen peroxide (H₂O₂), molecular oxygen (O₂), atomic oxygen (O), sulfur trioxide (SO₃), or an oxygen based plasma, wherein the oxygen based plasma comprises atomic oxygen (O), oxygen ions, oxygen radicals, and excited oxygen species, and may be generated by the excitation (e.g., by application of RF power) of an oxygen containing gas. It should be noted that as used herein the term “vapor phase reactant” includes an excited plasma and the excited species comprising the plasma.

In some embodiments of the disclosure, contacting the substrate with the oxygen containing precursor may comprise, contacting the oxygen precursor to the substrate for a time period of between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. In addition, during the contacting of the substrate with the oxygen precursor, the flow rate of the oxygen precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. In addition, during the contacting of the oxygen precursor to the substrate the flow rate of the oxygen precursor may range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

Upon contacting the substrate with the oxygen precursor, the exemplary rhenium oxide formation process 100 may proceed by purging the reaction chamber. For example, excess oxygen precursor and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping whilst flowing an inert gas. In some embodiments of the disclosure, the purge process may comprise purging the substrate surface for a time period of between approximately 0.1 seconds and approximately 10 seconds, or between approximately 0.5 seconds and approximately 3 seconds, or even between approximately 1 second and 2 seconds.

Upon completion of the purge of the second vapor phase reactant, i.e., the oxygen precursor (and any reaction byproducts) from the reaction chamber, the cyclic deposition phase 105 of exemplary rhenium oxide formation process 100 may continue with a decision gate 140, wherein the decision gate 140 is dependent on the thickness of the rhenium oxide film deposited. For example, if the rhenium oxide film is deposited at an insufficient thickness for a desired device application, then the cyclical deposition phase 105 may be repeated by returning to the process block 120 and continuing through a further deposition cycle, wherein a unit deposition cycle may comprise, contacting the substrate with a rhenium precursor (process block 120), purging the reaction chamber, contacting the substrate with an oxygen containing precursor (process block 130), and again purging the reaction chamber. A unit deposition cycle of cyclical deposition phase 105 may be repeated one or more times until a desired thickness of a rhenium oxide film is deposited over the substrate. Once the rhenium oxide film has been deposited to the desired thickness the exemplary process 100 may exit via a process block 150 and the substrate, with the rhenium oxide film deposited thereon, may be subjected to further processing for the formation of a device structure.

It should be appreciated that in some embodiments of the disclosure, the order of contacting of the substrate with the first vapor phase reactant (e.g., the rhenium precursor) and the second vapor phase reactant (e.g., the oxygen precursor) may be such that the substrate is first contacted with the second vapor phase reactant followed by the first vapor phase reactant. In addition, in some embodiments, the cyclical deposition phase 105 of exemplary process 100 may comprise, contacting the substrate with the first vapor phase reactant one or more times prior to contacting the substrate with the second vapor phase reactant one or more times. In addition, in some embodiments, the cyclical deposition phase 105 of exemplary process 100 may comprise, contacting the substrate with the second vapor phase reactant one or more times prior to contacting the substrate with the first vapor phase reactant one or more times.

As a non-limiting example, the reaction chamber may comprise an ALD reactor and the substrate may be heated to a temperature of approximately 200° C. (process block 110). The substrate may then be subjected to one or more deposition cycles of the cyclical deposition phase 105 which may comprise, contacting the substrate with ReOF₂, or ReOF₄, and subsequently contacting the substrate with water vapor, or ozone, thereby forming a rhenium trioxide (ReO₃) film.

As a further non-limiting example, the reaction chamber may comprise an ALD reactor and the substrate may be heated to a temperature of approximately 180° C. (process block 110). The substrate may then be subjected to one or more deposition cycles of cyclical deposition phase 105 which may comprise, contacting the substrate with ReOF₅ and subsequently contacting the substrate with water vapor, thereby forming rhenium (VII) oxide (Re₂O₇) films.

In some embodiments, the substrate may then be subjected to one or more deposition cycles of cyclical deposition phase 105 which may comprise, contacting the substrate with ReOCl, or ReOF, and subsequently contacting the substrate with oxygen, ozone, hydrogen peroxide, or water vapor, thereby forming rhenium (IV) oxide (ReO₂) films.

An additional exemplary rhenium oxide formation process may be understood with reference to FIG. 2 which illustrates a cyclical deposition process 200 for forming a rhenium oxide film.

In more detail, the cyclical deposition process 200 may commence with a process block 110 comprising, providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. The process block 110 has been described in detail with reference to FIG. 1 (cyclical deposition process 100) and therefore the details of the process block 110 are not repeated with respect to the cyclical deposition process 200.

Upon heating the substrate to the desired deposition temperature, within a suitable reaction chamber, the cyclical deposition process 200 may continue with the cyclical deposition phase 105 comprising, cyclically depositing a rhenium oxide film to a desired thickness. The cyclical deposition phase 105 for depositing a rhenium oxide film has been described in detail previously with reference to FIG. 1 (exemplary process 100) and therefore described in abbreviated form with respect to cyclical deposition process 200. In more detail, cyclical deposition phase 105 may comprise one or more cyclical deposition cycles, wherein a unit deposition cycle comprises, contacting the substrate with a rhenium precursor, purging the reaction chamber of excess rhenium precursor and any reaction by-products, contacting the substrate with an oxygen containing precursor, and purging the reaction chamber of excess oxygen precursor and any reaction by-products.

As a non-limiting example, the cyclical deposition phase 105 may comprise contacting the substrate with a rhenium oxyfluoride, such as, for example ReOF₅, and contacting the substrate with water vapor (H₂O) thereby depositing a rhenium oxide film, such as, for example, rhenium (VII) oxide (Re₂O₇).

In some embodiments, an intermittent reduction stage, i.e., contacting the deposited rhenium oxide film with a reducing agent precursor, can be applied after depositing a certain thickness of the rhenium oxide film. For example, a reduction stage may be applied to the rhenium oxide film after depositing a thickness of rhenium oxide of approximately 0.5 Angstroms, or after depositing less than 1 nanometer, or after depositing less than 3 nanometers, or after depositing less than or equal to 5 nanometers, or even after depositing greater than 5 nanometers.

As a further non-limiting example, the cyclical deposition phase 105 may comprise contacting the substrate with a rhenium oxyfluoride, such as, for example ReOF₄, and contacting the substrate with water vapor (H₂O) thereby depositing a rhenium oxide film, such as, for example, rhenium trioxide (ReO₃).

In some embodiments of the disclosure, the cyclical deposition phase 105 may be utilized to deposit a rhenium oxide film to a thickness of less than 1 Angstrom, or less than 2 Angstrom, or less than 5 Angstrom, or less than 10 Angstroms, or even less than 100 Angstroms. In some embodiments of the disclosure, the cyclical deposition phase 105 may be utilized to deposit a rhenium oxide film to a thickness which may be entirely reduced by subsequently contacting the rhenium oxide film with a reducing agent precursor (“the reducing stage”), whereas in some alternative embodiments the cyclical deposition phase 105 may be utilized to deposit a rhenium oxide to a thickness which may be only partially reduced by subsequently contacting the rhenium oxide film with a reducing agent precursor.

Upon forming a rhenium oxide film to a desired thickness the exemplary process 200 may proceed by means of a process block 220 comprising, contacting the substrate, and particularly contacting the rhenium oxide film, with a reducing agent precursor. In some embodiments, the reducing agent precursor may comprise a dione, such as, for example, 2,5-Hexanedione, cyclohexene-1,4-dione, or cyclohexane dione. In some embodiments the reducing agent precursor may comprise an acid, or carboxylic acid, such as, for example, glyoxylic acid (OCHCO₂H), formic acid (HCOOH), hydrogen halides like HCl, HF, HI, HBr, or oxalic acid (COOH)₂. In some embodiments, the reducing agent precursor may comprise an ethylene oxide (C₂H₄O), or ethylene carbonate. In some embodiments the reducing agent precursor may comprise anhydrides, such as, but not limited to, acetic anhydride (CH₃CO)₂O, phthalic anhydride, or maleic anhydride C₂H₂(CO)₂O. In some embodiments, the reducing agent precursor may comprise carbon monoxide (CO), nitrogen monoxide (NO), sulfur monoxide (SO), sulfur dioxide (SO₂), hydrogen (H₂), hydrazine (N₂H₄), forming gas (H₂+N₂), ammonia (NH₃), or an ammonia-hydrogen (NH₃—H₂) mixture.

In some embodiments of the disclosure, contacting the substrate with a reducing agent precursor may comprise contacting the reducing agent precursor to the substrate for a time period of between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. In addition, during the contacting of the substrate with the reducing agent precursor, the flow rate of the reducing agent precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. In addition, during the contacting of the reducing agent precursor to the substrate the flow rate of the reducing agent precursor may range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

As a non-limiting example, the cyclical deposition phase 105 of exemplary process 200 may deposit a rhenium (VII) oxide (Re₂O₇) film to a thickness of approximately less than 100 Angstroms and subsequently the rhenium (VII) oxide (Re₂O₇) film may be contacted with a reducing agent precursor, such as, but not limited, to carbon monoxide (CO), for a time period greater than 1 second at a substrate temperature of less than 250° C., or for a time period greater than 100 seconds at a substrate temperature of less than 350° C. For example, the reducing agent precursor may comprise a carbon monoxide (CO), a nitrogen monoxide (NO), or a sulfur monoxide (SO) vapor, which may contact the rhenium (VII) oxide (Re₂O₇) film thereby reducing the film to form a rhenium trioxide (ReO₃) film.

As a further non-limiting example, the cyclical deposition phase 105 of exemplary process 200 may deposit a rhenium trioxide (ReO₃) film to a thickness of approximately less than 1000 Angstroms, or less than less than 500 Angstroms, or less than 100 Angstroms, or less than 10 Angstroms, or even less than 1 Angstrom and subsequently the rhenium trioxide (ReO₃) film may be contacted with a reducing agent precursor, such as, but not limited to, carbon monoxide (CO), nitrogen monoxide (NO), glyoxylic acid (OCHCO₂H), 2,5-Hexanedione, cyclohexene-1,4-dione, cyclohexane dione, sulfur dioxide (SO₂), formic acid (HCOOH), acetic anhydride (CH₃CO)₂O, oxalic acid (COOH)₂ or maleic anhydride C₂H₂(CO)₂O, for a time period of less than 5 minutes, or less than 1 minute, or even less than 10 seconds, at a substrate temperature greater than 60° C., or at a substrate temperature greater than 120° C., or at a substrate temperature greater than 180° C., or even at a substrate temperature greater than 250° C. For example, the reducing agent precursor may comprise a nitrogen monoxide (NO) vapor which may contact the rhenium trioxide (ReO₃) film thereby reducing the film to form a rhenium (IV) oxide (ReO₂) film.

In some embodiments, the entirety of the rhenium oxide film deposited by the cyclical deposition phase 105 may be reduced by the contacting the rhenium oxide film with the reducing agent precursor, whereas in some alternative embodiments of the disclosure only a portion of the rhenium oxide film deposited by the cyclical deposition phase 105 may be reduced by contacting the rhenium oxide film with the reducing agent precursor.

Upon contacting the substrate with the reducing agent precursor, the exemplary rhenium oxide formation process 200 may proceed by purging the reaction chamber. For example, excess reducing agent precursor and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping whilst flowing an inert gas. In some embodiments of the disclosure, the purge process may comprise purging the substrate surface for a time period of between approximately 0.1 seconds and approximately 10 seconds, or between approximately 0.5 seconds and approximately 3 seconds, or even between approximately 1 second and 2 seconds.

Upon completion of the purge of the excess reducing agent precursor (and any reaction byproducts) from the reaction chamber, the exemplary rhenium oxide formation process 200 may continue with a decision gate 240, wherein the decision gate 240 is dependent on the thickness of the rhenium oxide film formed. For example, if the rhenium oxide film is formed at an insufficient thickness for a desired device application, then the cyclical deposition phase 205 of exemplary process 200 may be repeated by returning to the cyclical deposition phase 105 and continuing through one or more cyclical deposition cycles 205, wherein a unit deposition cycle of the cyclical deposition phase 205 may comprise, cyclically depositing a rhenium oxide film to a desired thickness (cyclical deposition phase 105), purging the reaction chamber, contacting the substrate with a reducing agent precursor (process block 220), and again purging the reaction chamber. A unit deposition cycle of cyclical deposition phase 205 may be repeated one or more times until a desired thickness of a rhenium oxide film with the desired composition is formed over the substrate. Once the rhenium oxide film has been formed to the desired thickness and composition the exemplary process 200 may exit via a process block 250 and the substrate, with the rhenium oxide film formed thereon, may be subjected to further processing for the formation of a device structure.

A further exemplary rhenium oxide formation process may be understood with reference to FIG. 3 which illustrates a cyclical deposition process 300 for forming a rhenium oxide film.

In more detail, the cyclical deposition process 300 may commence with a process block 110 comprising, providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. The process block 110 has been described in detail with reference to FIG. 1 (cyclical deposition process 100) and therefore the details of the process block 110 are not repeated with respect to the cyclical deposition process 300.

Upon heating the substrate to the desired deposition temperature within a suitable reaction chamber, the cyclical deposition process 300 may continue by utilizing either cyclical deposition phase 105 (of process 100, FIG. 1 ) or cyclical deposition phase 205 (of process 200, FIG. 2 ). Both cyclical deposition phase 105 and cyclical deposition phase 205 have been described in detail previously and therefore described in abbreviated form with respect to cyclical deposition process 300.

In more detail, in some embodiments, the cyclical deposition phase 105 may be utilized to deposit a rhenium oxide to a desired thickness and composition and may comprise one or more unit cycles of the cyclical deposition phase 105 wherein a unit cycle may comprise, contacting the substrate with a rhenium precursor, purging the reaction chamber of excess rhenium precursor and any reaction by-products, contacting the substrate with an oxygen containing precursor, and purging the reaction chamber of excess oxygen precursor and any reaction by-products. In some alternative embodiments, the cyclical deposition phase 205 may be utilized to deposit a rhenium oxide to a desired thickness and composition and may comprise one or more unit cycles of the cyclical deposition phase 205 wherein a unit cycle may comprise, cyclically depositing a rhenium oxide film to a desired thickness, purging the reaction chamber of excess precursor and any reaction by-products, contacting the substrate with a reducing agent precursor, and purging the reaction chamber of excess reducing agent precursor and any reaction by-products.

As a non-limiting example, the cyclical deposition phase 105 may be utilized by contacting the substrate with a rhenium oxyfluoride, such as, for example ReOF₄, and contacting the substrate with water vapor (H₂O) thereby depositing a rhenium oxide film, such as, for example, rhenium trioxide (ReO₃).

As a further non-limiting example, the cyclical deposition phase 205 may be utilized to form a rhenium oxide film, e.g., a rhenium trioxide (ReO₃), to a desired thickness, and contacting the rhenium trioxide (ReO₃) with a reducing agent precursor thereby forming a rhenium (IV) oxide (ReO₂) film to a desired thickness.

In some embodiments of the disclosure, the cyclical deposition phases 105 and 205 may be utilized to form a rhenium oxide film to a thickness of less than 1000 Angstroms, or less than 500 Angstroms, or less than 100 Angstroms, or even less than 10 Angstroms. In some embodiments of the disclosure, the cyclical deposition phases 105 and 205 may be utilized to deposit a rhenium oxide film to a thickness which may be entirely oxidized by subsequently contacting the rhenium oxide film with an additional oxygen containing precursor, whereas in some alternative embodiments the cyclical deposition phases 105 and 205 may be utilized to form a rhenium oxide to a thickness which may be only partially oxidized by subsequently contacting the rhenium oxide film with an additional oxygen containing precursor.

Upon forming a rhenium oxide film to a desired thickness and composition, the exemplary process 300 may proceed by means of a process block 320 comprising, contacting the substrate, and particularly contacting the rhenium oxide film, with an additional oxygen containing precursor.

In some embodiments of the disclosure, the additional oxygen containing precursor may comprise at least one of water (H₂O), ozone (O₃), formic acid (CH₂O₂), hydrogen peroxide (H₂O₂), molecular oxygen (O₂), atomic oxygen (O), sulfur trioxide (SO₃), or an oxygen based plasma, wherein the oxygen based plasma comprises atomic oxygen (O), oxygen ions, oxygen radicals, and excited oxygen species, and may be generated by the excitation (e.g., by application of RF power) of an oxygen containing gas. It should be noted that as used herein the term “vapor phase reactant” includes an excited plasma and the excited species comprising the plasma.

In some embodiments of the disclosure, contacting the substrate with the additional oxygen containing precursor may comprise, contacting the additional oxygen precursor to the substrate for a time period of between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. In addition, during the contacting of the additional oxygen precursor with the substrate, the flow rate of the additional oxygen precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. In addition, during the contacting of the additional oxygen precursor to the substrate the flow rate of the additional oxygen precursor may range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

As a non-limiting example, the cyclical deposition phase 105 of exemplary process 300 may be utilized to deposition a rhenium trioxide film (ReO₃) to a thickness of approximately less than 1000 Angstroms, or less than 500 Angstroms, or less than 100 Angstroms, or even less than 1 Angstrom and subsequently the rhenium trioxide (ReO₃) film may be contacted with an additional oxygen precursor, such as, for example, oxygen, water, an oxygen containing plasma, ozone, acetic acid, or hydrogen peroxide, for a time period of less than or equal to 10 minutes, or less than 1 minute, or even less than 10 seconds, at a substrate temperature of less than 400° C., or less than 300° C., or less than 200° C., or even less than 100° C. For example, the additional oxygen containing precursor may comprise ozone (O₃) which may contact the rhenium trioxide film (ReO₃) thereby oxidizing the film to form a rhenium (VII) oxide (Re₂O₇) film.

As an additional non-limiting example, the cyclical deposition phase 105 of exemplary process 300 may be utilized to deposition a rhenium (IV) oxide (ReO₂) film to a thickness of approximately less than 1000 Angstroms, or less than 500 Angstroms, or less than 100 Angstroms, or even less than 10 Angstroms and subsequently the rhenium (IV) oxide (ReO₂) film may be contacted with an additional oxygen precursor, such as, for example, oxygen, water, an oxygen containing plasma, ozone, acetic acid, or hydrogen peroxide, for a time period of less than or equal to 10 minutes, or less than 1 minute, or even less than 10 seconds, at a substrate temperature of less than 400° C., or less than 300° C., or less than 200° C., or even less than 100° C. For example, the additional oxygen containing precursor may comprise hydrogen peroxide (H₂O₂) which may contact the rhenium (IV) oxide (ReO₂) film thereby oxidizing the film to form a rhenium (VII) oxide (Re₂O₇) film.

As a further non-limiting example, the cyclical deposition phase 205 of exemplary process 300 may be utilized to form a rhenium (IV) oxide (ReO₂) film to a thickness of approximately less than 1000 Angstroms, or less than 500 Angstroms, or less than 100 Angstroms, or less than 10 Angstroms and subsequently the rhenium (IV) oxide (ReO₂) film may be contacted with an additional oxygen precursor, such as, for example, oxygen, water, an oxygen containing plasma, ozone, acetic acid, or hydrogen peroxide, for a time period of less than or equal to 10 minutes, or less than 1 minute, or even less than 10 seconds, at a substrate temperature of less than 400° C., or less than 300° C., or less than 200° C., or even less than 100° C. For example, the additional oxygen containing precursor may comprise an oxygen based plasma which may contact the rhenium (IV) oxide (ReO₂) film thereby oxidizing the film to form a rhenium (VII) oxide (Re₂O₇) film.

Therefore, in some embodiments of the disclosure, the rhenium oxide film comprises at least one of a rhenium (IV) oxide (ReO₂) film, or a rhenium trioxide (ReO₃) film, and the methods of the disclosure further comprises contacting the rhenium oxide film with an additional oxygen containing precursor thereby forming a rhenium (VII) oxide (Re₂O₇) film.

Upon contacting the substrate with the additional oxygen precursor, the exemplary rhenium oxide formation process 300 may proceed by purging the reaction chamber. For example, excess additional oxygen precursor and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping whilst flowing an inert gas. In some embodiments of the disclosure, the purge process may comprise purging the substrate surface for a time period of between approximately 1 second and approximately 100 seconds, or between approximately 0.1 seconds and approximately 10 seconds, or between approximately 0.5 seconds and approximately 3 seconds, or even between approximately 1 second and 2 seconds.

Upon completion of the purge of the excess additional oxygen precursor (and any reaction byproducts) from the reaction chamber, the exemplary rhenium oxide formation process 300 may continue with a decision gate 340, wherein the decision gate 340 is dependent on the thickness of the rhenium oxide film formed. For example, if the rhenium oxide film is formed at an insufficient thickness for a desired device application, then a cyclical deposition phase 305 may be repeated by returning to the cyclical deposition phase 105 or 205 and continuing through cyclical deposition phase 305, wherein a unit deposition cycle of the cyclical deposition phase 305 may comprise, forming a rhenium oxide film to a desired thickness and composition (cyclical phases 105 or 205), purging the reaction chamber, contacting the substrate with an additional oxygen containing precursor (process block 320), and again purging the reaction chamber. A unit deposition cycle of the cyclical deposition phase 305 may be repeated one or more times until a desired thickness of a rhenium oxide film with the desired composition is formed over the substrate. Once the rhenium oxide film has been formed to the desired thickness and composition the exemplary process 300 may exit via a process block 350 and the substrate, with the rhenium oxide film formed thereon, may be subjected to further processing for the formation of a device structure.

In some embodiments of the disclosure, the rhenium oxide films formed by the exemplary processes disclosed herein may comprise dielectric materials. For example, a rhenium (VII) oxide (Re₂O₇) film, or a rhenium (IV) oxide (ReO₂) film formed by the methods of the disclosure may comprise a dielectric material.

In some embodiments of the disclosure, the rhenium oxide films formed by the exemplary processes disclosed herein may comprise a conductive rhenium oxide film. In some embodiments, the conductive phase of the rhenium oxide films may comprise rhenium (IV) oxide (ReO₂) films, or rhenium trioxide (ReO₃) films. In some embodiments, the conductive rhenium oxide films may comprise a sub-oxide with the general formula ReO_(x) where x is less than 2. In some embodiments, the conductive phase of the rhenium oxide films formed by the embodiments of the disclosure may have an electrical resistivity as-deposited of less than 1000 μΩ-cm, or less than 700 μΩ-cm, or less than 500 μΩ-cm, or less than 250 μΩ-cm, or less than 100 μΩ-cm, or less than 50 μΩ-cm, or less than 25 μΩ-cm, or less than 10 μΩ-cm, or even less than 5 μΩ-cm. In some embodiments, the conductive phase of the rhenium oxide films formed by embodiments of the disclosure may have an electrical resistivity as-deposited between 5 μΩ-cm and 1000 μΩ-cm.

In some embodiments of the disclosure, the rhenium oxide films formed according to the embodiments of the disclosure may be subjected to one or more further processes to further improve the electrical resistivity of the rhenium oxide films.

In more detail, FIGS. 4A-4C illustrate cross-sectional schematic diagrams of semiconductor structures formed utilizing an exemplary process for forming a low resistivity conducting rhenium oxide film. In some embodiments, the methods of the disclosure may comprise providing a substrate, such as a substrate 400 of FIG. 4A. Substrate 400 may comprise a non-planar or planar (as illustrated) and may further comprise one or more materials as previously disclosed with reference to the process block 110 of FIG. 1 .

The substrate 400 may be provided into a suitable reaction chamber, such as, for example, an atomic layer deposition (ALD) reaction chamber and heated to a desired deposition temperature. Upon heating the substrate to the desired deposition temperature a rhenium oxide film 402 (FIG. 4B) may be deposited over the substrate 400 utilizing one of exemplary processes 100 (FIG. 1 ), 200 (FIG. 2 ), or 300 (FIG. 3 ). In some embodiments, the rhenium oxide film 402 comprises a conductive rhenium oxide film. In some embodiments, the conductive rhenium oxide film 402 may comprise at least one of rhenium (IV) oxide (ReO₂), or rhenium trioxide (ReO₃). In some embodiments, the conductive rhenium oxide films may comprise a sub-oxide with the general formula ReO_(x) where x is less than 2. In some embodiments, the conductive rhenium oxide film may be formed to a thickness of less 1000 Angstroms, or less than 500 Angstroms, or less than 250 Angstroms, or less than 100 Angstroms, or less than 50 Angstroms, or even less than 20 Angstroms, and may have an electrical resistivity of less than 1000 μΩ-cm, or less than 500 μΩ-cm, or less than 100 μΩ-cm, or less than 50 μΩ-cm, or even less than 20 μΩ-cm.

In some embodiments of the disclosure, the method of formation of a low electrical resistivity conductive rhenium oxide film may further comprise forming a capping layer over a surface of the rhenium oxide film. For example, a capping layer 404 may be deposited directly over the upper exposed surface of the rhenium oxide film 402 thereby forming the semiconductor structure 406, as illustrated in FIG. 4C. In some embodiments, the capping layer 404 may comprise a conductive layer, such as, for example, titanium nitride (TiN), tantalum nitride (TaN), tantalum (Ta), tungsten carbide (WC), molybdenum (Mo), or niobium boride (NbB). Not to be bound by any particular theory or mechanism, it is believed that the addition of a capping layer over the surface of the rhenium oxide film may prevent, or substantially prevent, the sublimation of the rhenium oxide film.

Upon deposition of the capping layer 404 over a surface of the rhenium oxide film 402, the methods of the disclosure may further comprise thermally annealing the rhenium oxide film 402. For example, the semiconductor structure 406 including the rhenium oxide film 402 may be thermally annealed at a temperature greater than 50° C., or greater than 100° C., or greater than 200° C., or greater than 300° C., or even greater than 400° C., or can be in the temperature range between 50° C. and 400° C. In some embodiments, thermally annealing the rhenium oxide film 402 may further comprise increasing the grain size of the crystallites comprising the rhenium oxide film 402. In some embodiments, thermally annealing the rhenium oxide film 402 may further comprise forming a substantially single crystalline rhenium oxide film. In some embodiments, thermally annealing the rhenium oxide film 402 may further comprise reducing the density of grain boundaries within the rhenium oxide film. In some embodiments, thermally annealing the rhenium oxide film 402 may further comprise reducing the electrical resistivity of the rhenium oxide film. For example, the rhenium oxide film post thermal annealing may have an electrical resistivity of less than 1000 μΩ-cm, or less than 100 μΩ-cm, or even less than 10 μΩ-cm.

Exemplary Cyclical Deposition Processes for the Formation of Rhenium Sulfide Films

In some embodiments of disclosure, a cyclical deposition process may be utilized to form a rhenium sulfide of general formulae ReS_(a) or Re_(x)S_(y) where a, x, and y are less than or equal to 7, such as, for example, rhenium disulfide (ReS₂), or dirhenium hepta sulfide (Re₂S₇). In some embodiments, the cyclical deposition process may comprise, forming the rhenium sulfide film by the surface reaction between a first vapor phase reactant and a second vapor phase reactant. In some embodiments, the cyclical deposition process may comprise forming an intermediate rhenium oxide film followed by contacting the intermediate rhenium oxide film with a sulfur containing precursor.

An exemplary rhenium sulfide formation process may be understood with reference to FIG. 5 which illustrates an exemplary cyclical deposition process 500 for the forming of a rhenium sulfide film.

In more detail, the cyclical deposition process 500 may commence with a process block 110 comprising, providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. The process block 110 has been described in detail with reference to FIG. 1 (cyclical deposition process 100) and therefore the details of the process block 110 are not repeated with respect to the cyclical deposition process 500.

Upon heating the substrate to the desired deposition temperature within a suitable reaction chamber, the cyclical deposition process 500 may continue by means of the process of a cyclical deposition phase 505 which may commence via a process block 120. The process block 120 has been previously described in detail with reference to FIG. 1 (cyclical deposition process 100) and therefore appears in abbreviated form with respect to cyclical deposition process 500.

In more detail, the process block 120 may comprise contacting the substrate with a rhenium precursor. In some embodiments, the rhenium precursor may comprise a rhenium halide, such as, for example, a rhenium chloride, a rhenium bromide, a rhenium fluoride, or a rhenium iodide. In particular embodiments, the rhenium precursor may comprise a rhenium oxyhalide, such as, for example, a rhenium oxychloride, or rhenium oxyfluoride. In some embodiments the rhenium oxyhalide may comprise at least one of ReOF₄, ReOF₅, ReO₂F₂, or ReO₂Cl₃. In some embodiments, the rhenium precursor may comprise an alkyl rhenium oxide precursor; a cyclopentadienyl based rhenium precursor, or a rhenium carbonyl halide precursor.

The exemplary rhenium sulfide formation process 500 of FIG. 5 may continue by purging the reaction chamber. For example, excess rhenium precursor and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping with an inert gas. In some embodiments of the disclosure, the purge process may comprise a purge cycle wherein the substrate surface is purged for a time period of less than approximately 5.0 seconds, or less than approximately 3.0 seconds, or even less than approximately 2.0 seconds. Excess rhenium precursor and any possible reaction byproducts may be removed with the aid of a vacuum, generated by a pumping system in fluid communication with the reaction chamber.

The cyclical deposition phase 505 of exemplary rhenium sulfide formation process 500 may continue by means of a process block 530 comprising, contacting the substrate with a sulfur containing precursor (“the sulfur precursor”). In some embodiments, the sulfur containing precursor comprises at least one of hydrogen sulfide (H₂S), sulfur dioxide (SO₂), carbon disulfide (CS₂), dimethyl sulfide (C₂H₆S), methanethiol (CH₃SH), or a dialkyl disulfide.

In some embodiments of the disclosure, contacting the substrate with the sulfur containing precursor may comprise, contacting the sulfur precursor to the substrate for a time period of between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. In addition, during the contacting of the substrate with the sulfur precursor, the flow rate of the sulfur precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. In addition, during the contacting of the substrate with the sulfur precursor, the flow rate of the sulfur precursor may range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

The exemplary rhenium sulfide formation process 500 of FIG. 5 may continue by purging the reaction chamber. For example, excess sulfur precursor and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping with an inert gas. In some embodiments of the disclosure, the purge process may comprise a purge cycle wherein the substrate surface is purged for a time period of less than approximately 5.0 seconds, or less than approximately 3.0 seconds, or even less than approximately 2.0 seconds. Excess sulfur precursor and any possible reaction byproducts may be removed with the aid of a vacuum, generated by a pumping system in fluid communication with the reaction chamber.

Upon completion of the purge of the excess sulfur precursor (and any reaction byproducts) from the reaction chamber, the exemplary rhenium sulfide formation process 500 may continue with a decision gate 540, wherein the decision gate 540 is dependent on the thickness of the rhenium sulfide film deposited. For example, if the rhenium sulfide film is deposited at an insufficient thickness for a desired device application, then the cyclical deposition phase 505 may be repeated by returning to the process block 120 and continuing through cyclical deposition phase 505, wherein a unit deposition cycle of the cyclical deposition phase 505 may comprise, contacting the substrate with a rhenium oxyhalide precursor (process block 120), purging the reaction chamber, contacting the substrate with a sulfur containing precursor (process block 530), and again purging the reaction chamber. A unit deposition cycle of cyclical deposition phase 505 may be repeated one or more times until a desired thickness of a rhenium sulfide film with the desired composition is formed over the substrate. Once the rhenium sulfide film has been deposited to the desired thickness and composition the exemplary process 500 may exit via a process block 550 and the substrate, with the rhenium sulfide film formed thereon, may be subjected to further processing for the formation of a device structure.

It should be appreciated that in some embodiments of the disclosure, the order of contacting of the substrate with the first vapor phase reactant (e.g., the rhenium precursor) and the second vapor phase reactant (e.g., the sulfur precursor) may be such that the substrate is first contacted with the second vapor phase reactant followed by the first vapor phase reactant. In addition, in some embodiments, the cyclical deposition phase 505 of exemplary process 500 may comprise, contacting the substrate with the first vapor phase reactant one or more times prior to contacting the substrate with the second vapor phase reactant one or more times. In addition, in some embodiments, the cyclical deposition phase 505 of exemplary process 500 may comprise, contacting the substrate with the second vapor phase reactant one or more times prior to contacting the substrate with the first vapor phase reactant one or more times.

As a non-limiting example, the reaction chamber may comprise an ALD reactor and the substrate may be heated to a temperature between approximately 100° C. and approximately 400° C. (process block 110). The substrate may then be subjected to one or more deposition cycles of cyclical deposition phase 505 which may comprise, contacting the substrate with ReO₂F₂, and subsequently contacting the substrate with hydrogen sulfide (H₂S), thereby forming a rhenium disulfide (ReS₂) film.

A further exemplary rhenium sulfide formation process may be understood with reference to FIG. 6 which illustrates a cyclical deposition process 600 for forming a rhenium sulfide film.

In more detail, the cyclical deposition process 600 may commence with a process block 110 comprising, providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. The process block 110 has been described in detail with reference to FIG. 1 (cyclical deposition process 100) and therefore the details of the process block 110 are not repeated with respect to the cyclical deposition process 600.

Upon heating the substrate to the desired deposition temperature within a suitable reaction chamber, the cyclical deposition process 600 may continue by forming a rhenium oxide film to a desired thickness and composition utilizing either the cyclical deposition phase 105 (of process 100, FIG. 1 ), the cyclical deposition phase 205 (of process 200, FIG. 2 ), or the cyclical deposition phase 305 (of process 300, FIG. 3 ). Cyclical deposition phases 105, 205 and 305 have been described in detail previously and therefore the specifics of the cyclical deposition phases 105, 205, and 305 are not repeated with respect to the cyclical deposition process 600.

In some embodiments of the disclosure, the cyclical deposition phase 105, 205, or 305 may be utilized to form a rhenium oxide film, such as, for example, a rhenium (IV) oxide (ReO₂) film, a rhenium trioxide (ReO₃) film, or a rhenium (VII) oxide (Re₂O₇) film. In some embodiments, the rhenium oxide film may be formed to a thickness of less than 1000 Angstroms, or less than 500 Angstroms, or less than 250 Angstroms, or less than 100 Angstroms, or even less than 10 Angstroms.

In some embodiments of the disclosure, the rhenium oxide may be formed to a thickness which may be entirely converted to a rhenium sulfide film on subsequently contacting the rhenium oxide with a sulfur precursor, whereas in some alternative embodiments the rhenium oxide may be formed to a thickness which may be only be partially converted to a rhenium sulfide film on subsequently contacting the rhenium oxide with a sulfur precursor.

In some embodiments of the disclosure, the cyclical deposition phase 605 may continue by means of a process block 620 comprising, contacting the substrate with a sulfur containing precursor (“the sulfur precursor”). In some embodiments, the sulfur containing precursor may comprise at least one of hydrogen sulfide (H₂S), sulfur dioxide (SO₂), carbon disulfide (CS₂), dimethyl sulfide (C₂H₆S), methanethiol (CH₃SH), or a dialkyl disulfide.

In some embodiments of the disclosure, contacting the substrate, and particularly the rhenium oxide film with the sulfur containing precursor may comprise, contacting the sulfur precursor to the substrate for a time period of between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. In addition, during the contacting of the substrate with the sulfur precursor, the flow rate of the sulfur precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. In addition, during the contacting of the sulfur precursor to the substrate the flow rate of the sulfur precursor may range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

The exemplary rhenium sulfide formation process 600 of FIG. 6 may continue by purging the reaction chamber. For example, excess sulfur precursor and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping with an inert gas. In some embodiments of the disclosure, the purge process may comprise a purge cycle wherein the substrate surface is purged for a time period of less than approximately 5.0 seconds, or less than approximately 3.0 seconds, or even less than approximately 2.0 seconds. Excess sulfur precursor and any possible reaction byproducts may be removed with the aid of a vacuum, generated by a pumping system in fluid communication with the reaction chamber.

Upon completion of the purge of the excess additional sulfur precursor (and any reaction byproducts) from the reaction chamber, the exemplary rhenium sulfide formation process 600 may continue with a decision gate 640, wherein the decision gate 640 is dependent on the thickness of the rhenium sulfide film formed. For example, if the rhenium sulfide film is formed at an insufficient thickness for a desired device application, then the cyclical deposition phase 605 may be repeated by returning to the either cyclical phase 105, 205, or 305 for forming a rhenium oxide film to a desired thickness and composition and continuing through cycle deposition phase 605, wherein a unit deposition cycle of the cyclical deposition phase 605 may comprise, forming a rhenium oxide film to a desired thickness and composition (cyclical phases 105, 205, or 305), purging the reaction chamber, contacting the substrate with a sulfur precursor (process block 640), and again purging the reaction chamber. A unit deposition cycle of cyclical deposition phase 605 may be repeated one or more times until a desired thickness of a rhenium sulfide film with the desired composition is formed over the substrate. Once the rhenium sulfide film has been formed to the desired thickness and composition the exemplary process 600 may exit via a process block 650 and the substrate, with the rhenium sulfide film formed thereon, may be subjected to further processing for the formation of a device structure.

As a non-limiting example, the cyclical deposition phase 105 may be utilized in cyclical deposition process 600 to deposition a rhenium trioxide film (ReO₃) to a thickness of approximately less than 300 Angstroms and subsequently the rhenium trioxide (ReO₃) film may be contacted with a sulfur precursor, such as, for example, hydrogen sulfide (H₂S), sulfur monoxide (SO), sulfur dioxide (SO₂), carbon disulfide (CS₂), dimethyl sulfide (C₂H₆S) or methanethiol (CH₃SH), for a time period of less than 10 minutes, or less than 5 minutes, or less than 1 minute, or even less than 10 seconds, at a substrate temperature in the range between 100° C. and 400° C., or between 150° C. and 300° C. For example, the sulfur containing precursor may comprise hydrogen sulfide (H₂S) which may contact the rhenium trioxide film (ReO₃) thereby converting the rhenium oxide film to form a rhenium disulfide (ReS₂), dirhenium heptasulfide (Re₂S₇) or a rhenium sulfide of general formulae ReS_(a) where a is a non-integer number less than 3.5.

Exemplary Cyclical Deposition Processes for the Formation of Elemental Rhenium Films

In some embodiments of disclosure, a cyclical deposition process may be utilized to form an elemental rhenium film. In some embodiments, the cyclical deposition process may comprise forming the elemental rhenium film by the surface reaction between a first vapor phase reactant and a second vapor phase reactant. In some embodiments, the cyclical deposition process may comprise forming an intermediate rhenium oxide film followed by contacting the intermediate rhenium oxide film with a hydrogen containing precursor thereby forming the elemental rhenium film.

An exemplary elemental rhenium formation process may be understood with reference to FIG. 7 which illustrates an exemplary cyclical deposition process 700 for the forming of an elemental rhenium film.

In more detail, the cyclical deposition process 700 may commence with a process block 110 comprising, providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. The process block 110 has been described in detail with reference to FIG. 1 (cyclical deposition process 100) and therefore the details of the process block 110 are not repeated with respect to the cyclical deposition process 700.

Upon heating the substrate to the desired deposition temperature within a suitable reaction chamber, the cyclical deposition process 700 may continue by means of the process of a cyclical deposition phase 705 which may commence via a process block 120. The process block 120 has been previously described in detail with reference to FIG. 1 (cyclical deposition process 100) and therefore appears in abbreviated form with respect to cyclical deposition process 700.

In more detail, the process block 120 may comprise contacting the substrate with a rhenium precursor. In some embodiments, the rhenium precursor may comprise a rhenium halide, such as, for example, a rhenium chloride, a rhenium bromide, a rhenium fluoride, or a rhenium iodide. In particular embodiments, the rhenium precursor may comprise a rhenium oxyhalide, such as, for example, a rhenium oxychloride, or rhenium oxyfluoride. In some embodiments the rhenium oxyhalide may comprise at least one of ReOF₄, ReOF₅, ReO₂F₂, or ReO₂Cl₃. In some embodiments, the rhenium precursor may comprise, an alkyl rhenium oxide precursor; a cyclopentadienyl based rhenium precursor, or a rhenium carbonyl halide precursor.

The exemplary elemental rhenium formation process 700 of FIG. 7 may continue by purging the reaction chamber. For example, excess rhenium precursor and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping with an inert gas. In some embodiments of the disclosure, the purge process may comprise a purge cycle wherein the substrate surface is purged for a time period of less than approximately 5.0 seconds, or less than approximately 3.0 seconds, or even less than approximately 2.0 seconds. Excess rhenium precursor and any possible reaction byproducts may be removed with the aid of a vacuum, generated by a pumping system in fluid communication with the reaction chamber.

The cyclical deposition phase 705 of exemplary elemental rhenium formation process 700 may continue by means of a process block 730 comprising, contacting the substrate with a hydrogen containing precursor (“the hydrogen precursor”). In some embodiments, the hydrogen containing precursor comprises at least one hydrogen sulfide (H₂S), molecular hydrogen (H₂), atomic hydrogen (H), hydrazine (N₂H₄), forming gas (H₂+N₂), ammonia (NH₃), an ammonia-hydrogen (NH₃—H₂) mixture, or a hydrogen based plasma, wherein the hydrogen based plasma comprises atomic hydrogen (H), hydrogen ions, hydrogen radicals, and excited hydrogen species, and may be generated by the excitation (e.g., by application of RF power) of a hydrogen containing gas. It should be noted that as used herein the term “vapor phase reactant” includes an excited plasma and the excited species comprising the plasma.

In some embodiments of the disclosure, contacting the substrate with the hydrogen containing precursor may comprise, contacting the hydrogen precursor to the substrate for a time period of between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. In addition, during the contacting of the substrate with hydrogen precursor, the flow rate of the hydrogen precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. In addition, during the contacting of the substrate with the hydrogen precursor the flow rate of the hydrogen precursor may range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

The exemplary elemental rhenium formation process 700 of FIG. 7 may continue by purging the reaction chamber. For example, excess hydrogen precursor and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping with an inert gas. In some embodiments of the disclosure, the purge process may comprise a purge cycle wherein the substrate surface is purged for a time period of less than approximately 5.0 seconds, or less than approximately 3.0 seconds, or even less than approximately 2.0 seconds. Excess hydrogen precursor and any possible reaction byproducts may be removed with the aid of a vacuum, generated by a pumping system in fluid communication with the reaction chamber.

Upon completion of the purge of the excess hydrogen precursor (and any reaction byproducts) from the reaction chamber, the exemplary elemental rhenium formation process 700 may continue with a decision gate 740, wherein the decision gate 740 is dependent on the thickness of the elemental rhenium film formed. For example, if the elemental rhenium film is formed at an insufficient thickness for a desired device application, then the cyclical deposition phase 705 may be repeated by returning to the process block 120 and continuing through cyclical deposition phase 705, wherein a unit deposition cycle of the cyclical deposition phase 705 may comprise, contacting the substrate with a rhenium precursor (process block 120), purging the reaction chamber, contacting the substrate with a hydrogen containing precursor (process block 730), and again purging the reaction chamber. A unit deposition cycle of cyclical deposition phase 705 may be repeated one or more times until a desired thickness of an elemental rhenium film is formed over the substrate. Once the elemental rhenium film has been deposited to the desired thickness the exemplary process 700 may exit via a process block 750 and the substrate, with the elemental rhenium film formed thereon, may be subjected to further processing for the formation of a device structure.

It should be appreciated that in some embodiments of the disclosure, the order of contacting of the substrate with the first vapor phase reactant (e.g., the rhenium precursor) and the second vapor phase reactant (e.g., the hydrogen precursor) may be such that the substrate is first contacted with the second vapor phase reactant followed by the first vapor phase reactant. In addition, in some embodiments, the cyclical deposition phase 705 of exemplary process 700 may comprise, contacting the substrate with the first vapor phase reactant one or more times prior to contacting the substrate with the second vapor phase reactant one or more times. In addition, in some embodiments, the cyclical deposition phase 705 of exemplary process 700 may comprise, contacting the substrate with the second vapor phase reactant one or more times prior to contacting the substrate with the first vapor phase reactant one or more times.

As a non-limiting example, the reaction chamber may comprise an ALD reactor and the substrate may be heated to a temperature of between approximately 150° C. and 300° C. (process block 110). The substrate may then be subjected to one or more deposition cycles of cyclical deposition phase 705 which may comprise, contacting the substrate with ReO₂F₂, and subsequently contacting the substrate with a hydrogen based plasma, thereby forming an elemental rhenium film.

A further exemplary elemental rhenium film formation process may be understood with reference to FIG. 8 which illustrates a cyclical deposition process 800 for forming an elemental rhenium film.

In more detail, the cyclical deposition process 800 may commence with a process block 110 comprising, providing a substrate into a reaction chamber and heating the substrate to a deposition temperature. The process block 110 has been described in detail with reference to FIG. 1 (cyclical deposition process 100) and therefore the details of the process block 110 are not repeated with respect to the cyclical deposition process 800.

Upon heating the substrate to the desired deposition temperature within a suitable reaction chamber, the cyclical deposition process 800 may continue by forming a rhenium oxide film to a desired thickness and composition utilizing either the cyclical deposition phase 105 (of process 100, FIG. 1 ), the cyclical deposition phase 205 (of process 200, FIG. 2 ), or the cyclical deposition phase 305 (of process 300, FIG. 3 ). Cyclical deposition phases 105, 205, and 305 have been described in detail previously and therefore the specifics of the cyclical deposition phases 105, 205, and 305 are not repeated with respect to the cyclical deposition process 800.

In some embodiments of the disclosure, the cyclical deposition phase 105, 205, or 305 may be utilized to form a rhenium oxide film, such as, for example, a rhenium (IV) oxide (ReO₂) film, a rhenium trioxide (ReO₃) film, or a rhenium (VII) oxide (Re₂O₇) film. In some embodiments, the rhenium oxide film may formed to a thickness of less than 1000 Angstroms, or less than 500 Angstroms, or less than 100 Angstroms, or less than 10 Angstroms, or even less than 5 Angstroms.

In some embodiments of the disclosure, the rhenium oxide may be formed to a thickness which may be entirely converted to an elemental rhenium film by subsequently contacting the rhenium oxide with a hydrogen precursor, whereas in some alternative embodiments the rhenium oxide may be formed to a thickness which may only be partially converted to an elemental rhenium film by subsequently contacting the rhenium oxide with a hydrogen precursor.

In some embodiments of the disclosure, the cyclical deposition phase 805 may continue by means of a process block 820 comprising, contacting the substrate with a hydrogen containing precursor (“the hydrogen precursor”). In some embodiments, the hydrogen containing precursor may comprise at least one of hydrogen sulfide (H₂S), hydrazine (N₂H₄), forming gas (H₂+N₂), ammonia (NH₃), an ammonia-hydrogen (NH₃—H₂) mixture, molecular hydrogen (H₂), atomic hydrogen (H), or a hydrogen based plasma, wherein the hydrogen based plasma comprises atomic hydrogen (H), hydrogen ions, hydrogen radicals, and excited hydrogen species, and may be generated by the excitation (e.g., by application of RF power) of a hydrogen containing gas.

In some embodiments of the disclosure, contacting the substrate, and particularly the rhenium oxide film with the hydrogen containing precursor may comprise, contacting the hydrogen precursor to the substrate for a time period of between about 0.01 seconds and about 60 seconds, between about 0.05 seconds and about 10 seconds, or between about 0.1 seconds and about 5.0 seconds. In addition, during the contacting of the substrate with the hydrogen precursor, the flow rate of the hydrogen precursor may be less than 2000 sccm, or less than 500 sccm, or even less than 100 sccm. In addition, during the contacting of the substrate with the hydrogen precursor the flow rate of the hydrogen precursor may range from about 1 to 2000 sccm, from about 5 to 1000 sccm, or from about 10 to about 500 sccm.

The exemplary elemental rhenium film formation process 800 of FIG. 8 may continue by purging the reaction chamber. For example, excess hydrogen precursor and reaction byproducts (if any) may be removed from the surface of the substrate, e.g., by pumping with an inert gas. In some embodiments of the disclosure, the purge process may comprise a purge cycle wherein the substrate surface is purged for a time period of less than approximately 5.0 seconds, or less than approximately 3.0 seconds, or even less than approximately 2.0 seconds. Excess hydrogen precursor and any possible reaction byproducts may be removed with the aid of a vacuum, generated by a pumping system in fluid communication with the reaction chamber.

Upon completion of the purge of the excess hydrogen precursor (and any reaction byproducts) from the reaction chamber, the exemplary elemental rhenium formation process 800 may continue with a decision gate 840, wherein the decision gate 840 is dependent on the thickness of the elemental rhenium film formed. For example, if the elemental rhenium film is formed at an insufficient thickness for a desired device application, then the cyclical deposition phase 805 may be repeated by returning to the either cyclical phase 105, 205, or 305 for forming a rhenium oxide film to a desired thickness and composition and continuing through deposition cycle phase 805, wherein a unit deposition cycle of the cyclical deposition phase 805 may comprise, forming a rhenium oxide film to a desired thickness and composition (cyclical phases 105, 205, or 305), purging the reaction chamber, contacting the substrate with a hydrogen precursor (process block 820), and again purging the reaction chamber. A unit deposition cycle of cyclical deposition phase 805 may be repeated one or more times until a desired thickness of an elemental rhenium film is formed over the substrate. Once the elemental rhenium film has been formed to the desired thickness the exemplary process 800 may exit via a process block 850 and the substrate, with the elemental rhenium film formed thereon, may be subjected to further processing for the formation of a device structure.

As a non-limiting example, the cyclical deposition phase 105 may be utilized in cyclical deposition process 800 to deposition a rhenium trioxide film (ReO₃) to a thickness of approximately less than 200 Angstroms and subsequently the rhenium trioxide (ReO₃) film may be contacted with a hydrogen precursor, such as, for example, hydrogen diatomic gas (H₂), a hydrogen containing plasma, ammonia (NH₃) an ammonia-hydrogen mixture (NH₃—H₂), or forming gas (H₂—N₂) for a time period of less than 10 minutes, or less than 5 minutes, or less than 1 minute, or even less than 10 seconds, at a substrate temperature in the temperature range between 80° C. and 400° C. For example, the hydrogen containing precursor may comprise a hydrogen based plasma which may contact the rhenium trioxide film (ReO₃) thereby converting the oxide film to form an elemental rhenium film.

Properties of Rhenium-Containing Films Formed by Cyclical Deposition Processes

In some embodiments of the disclosure, the growth rate of the rhenium-containing film, e.g., elemental rhenium films, rhenium oxide films, rhenium boride films, or rhenium sulfide films, may be from about 0.005 Angstroms/cycle to about 5 Angstroms/cycle, from about 0.01 Angstroms/cycle to about 2.0 Angstroms/cycle. In some embodiments, the growth rate of the rhenium-containing film may be from about 0.1 Angstroms/cycle to about 10 Angstroms/cycle. In some embodiments the growth rate of the rhenium-containing film is more than about 0.05 Angstroms/cycle, more than about 0.1 Angstroms/cycle, more than about 0.15 Angstroms/cycle, more than about 0.20 Angstroms/cycle, more than about 0.25 Angstroms/cycle, or even more than about 0.3 Angstroms/cycle. In some embodiments the growth rate of the rhenium-containing film is less than about 2.0 Angstroms/cycle, less than about 1.0 Angstroms/cycle, less than about 0.75 Angstroms/cycle, less than about 0.5 Angstroms/cycle, or less than about 0.2 Angstroms/cycle. In some embodiments of the disclosure, the rhenium-containing film may be deposited at a growth rate of approximately less than 2.5 Angstroms/cycle, or even less than 1 Angstroms/cycle.

The rhenium-containing films deposited by the methods disclosed herein may be continuous films. In some embodiments, the rhenium-containing film may be continuous at a thickness below approximately 100 Angstroms, or below approximately 60 Angstroms, or below approximately 50 Angstroms, or below approximately 40 Angstroms, or below approximately 30 Angstroms, or below approximately 20 Angstroms, or below approximately 10 Angstroms, or even below approximately 5 Angstroms. The continuity referred to herein can be physical continuity or electrical continuity. In some embodiments of the disclosure the thickness at which a material film may be physically continuous may not be the same as the thickness at which a film is electrically continuous, and vice versa.

In some embodiments of the disclosure, the rhenium-containing film formed according to the embodiments of the disclosure, may have a thickness from about 20 nanometers to about 100 nanometers, or about 20 nanometers to about 60 nanometers. In some embodiments, a rhenium-containing film deposited according to some of the embodiments described herein may have a thickness greater than about 20 nanometers, or greater than about 30 nanometers, or greater than about 40 nanometers, or greater than about 50 nanometers, or greater than about 60 nanometers, or greater than about 100 nanometers, or greater than about 250 nanometers, or greater than about 500 nanometers, or greater. In some embodiments a rhenium containing film deposited according to some of the embodiments described herein may have a thickness of less than about 50 nanometers, or less than about 30 nanometers, or less than about 20 nanometers, or less than about 15 nanometers, or less than about 10 nanometers, or less than about 5 nanometers, or less than about 3 nanometers, or even less than about 2 nanometers. In some embodiments, the rhenium-containing film may have a thickness between approximately 0.1 nanometers and 50 nanometers, or between 1 nanometer and 30 nanometers, or between 4 nanometers and 20 nanometers.

In some embodiments of the disclosure, the rhenium-containing films may be formed on a substrate comprising high aspect ratio features, e.g., a three-dimensional, non-planar substrate. In some embodiments, the step coverage of the rhenium-containing film may be equal to or greater than about 50%, or greater than about 80%, or greater than about 90%, or greater than about 95%, or greater than about 98%, or about 99% or greater on structures having aspect ratios (height/width) of greater than 2, or greater than 5, or greater than 10, or greater than 25, or greater than 50, or even greater than 100.

In some embodiments of the disclosure, the rhenium containing films may comprise, pure rhenium, or rhenium and hydrogen, or rhenium, hydrogen and oxygen, or rhenium, hydrogen, carbon and oxygen, or rhenium, sulfur and oxygen. In some embodiments the rhenium containing films may further comprise impurities including, but not limited to, a halide (e.g., chlorine, fluorine, iodine, or bromine), carbon, hydrogen, and nitrogen.

The rhenium-containing films formed according to the embodiments of the disclosure may be utilized in a variety of technology applications. As non-limiting examples conductive rhenium oxide films may be utilized as electrical interconnects, barrier layer films, as a portion of a Schottky diode device, as a portion of a metal-insulator-semiconductor (MIS) device, as a portion of a metal-insulator-metal (MIM) device, as a portion of gate electrode to a semiconductor device, such as NMOS or PMOS logic devices, or as an electrode to a semiconductor device structure, such as a DRAM device. In addition, certain rhenium oxide films, such as, for example, rhenium (VII) oxide (Re₂O₇), may exhibit dielectric properties and therefore may be utilized in DRAM devices, and in capacitor structures. Furthermore, rhenium sulfides, such as, for example, rhenium disulfide (ReS₂), may behave in a manner similar to 2D materials and may find applications in tribology, other low-frication applications, solar cell applications, quantum computing, and ultrafast data processing.

As a non-limiting example embodiment, the rhenium-containing film may comprise a conductive rhenium oxide film and may be utilized in semiconductor device structures including conductive interconnections for electrically connecting one or more semiconductor device structures.

In more detail, FIG. 9 illustrates a semiconductor device structure 900 which may comprise a substrate 902 which may include one or more semiconductor device structures (not shown) formed into or onto a surface of the substrate. For example, the substrate 902 may comprise partially fabricated and/or fabricated semiconductor device structures such as transistors and memory elements. The semiconductor device structure 900 may also comprise a dielectric material 904 formed over the substrate 902, wherein the dielectric material may comprise a low-dielectric constant material, a silicon oxide, a silicon nitride, a silicon oxynitride, or mixtures thereof. The semiconductor device structure 900 may further comprise a barrier material 906, which prevents, or substantially prevents, the diffusion of the conductive interconnect material 908 into the surrounding dielectric material 904. In some embodiments of the disclosure, the barrier material 906 may comprise a rhenium-containing material formed according to the embodiments of the disclosure, such as, for example, a conductive rhenium oxide. The semiconductor device structure 900 may further comprise a conductive interconnect material 908 which may be utilized to electrically connect semiconductor device structures formed in and/or on substrate 902. In some embodiments of the disclosure, the conductive interconnect material 908 may also comprise a rhenium-containing film formed according to the embodiments of the disclosure. For example, the conductive interconnect material 908 may comprise a conductive rhenium oxide or an elemental rhenium formed by the methods disclosed herein. The semiconductor device structure 900 may also comprise a capping layer 910, such as, for example, a conductive capping layer comprising titanium nitride (TiN), tantalum nitride (TaN), or tungsten (W).

Embodiments of the disclosure may also include a reaction system configured for forming the rhenium-containing films of the present disclosure. In more detail, FIG. 10 schematically illustrates a reaction system 1000 including a reaction chamber 1002 that further includes mechanism for retaining a substrate (not shown) under predetermined pressure, temperature, and ambient conditions, and for selectively exposing the substrate to various gases. A precursor reactant source 1004 may be coupled by conduits or other appropriate means 1004A to the reaction chamber 1002, and may further couple to a manifold, valve control system, mass flow control system, or mechanism to control a gaseous precursor originating from the precursor reactant source 1004. A precursor (not shown) supplied by the precursor reactant source 1004, the reactant (not shown), may be liquid or solid under room temperature and standard atmospheric pressure conditions. Such a precursor may be vaporized within a reactant source vacuum vessel, which may be maintained at or above a vaporizing temperature within a precursor source chamber. In such embodiments, the vaporized precursor may be transported with a carrier gas (e.g., an inactive or inert gas) and then fed into the reaction chamber 1002 through conduit 1004A. In other embodiments, the precursor may be a vapor under standard conditions. In such embodiments, the precursor does not need to be vaporized and may not require a carrier gas. For example, in one embodiment the precursor may be stored in a gas cylinder.

The reaction system 1000 may also include additional precursor reactant sources, such as precursor reactant source 1006, which may also be coupled to the reaction chamber by conduits 1006A as described above. The reaction system may include additional precursor reactant source 1008, which may also be coupled to the reaction chamber by conduits 1008A, as described above. The reaction system may also include further additional precursor reactant source 1009, which may also be couple to the reaction chamber by conduits 1009A, as described. In some embodiments of the disclosure, precursor reactant source 1004 may comprise a rhenium precursor, precursor reactant source 1006 may comprise at least one of an oxygen containing precursor, a sulfur containing precursor, a boron containing precursor, or a hydrogen containing precursor, precursor reactant source 1008 may comprise a reducing agent precursor, and precursor reactant source 1009 may comprise an oxidizing precursor. Therefore, in some embodiments of the disclosure, the exemplary cyclical deposition processes 100, 200, 300, 500, 600, 700, and 800 of the current disclosure may be performed in a single reaction chamber.

A purge gas source 1010 may also be coupled to the reaction chamber 1002 via conduits 1010A, and selectively supplies various inert or noble gases to the reaction chamber 1002 to assist with the removal of precursor gas or waste gases from the reaction chamber. The various inert or noble gases that may be supplied may originate from a solid, liquid or stored gaseous form.

The reaction system 1000 of FIG. 10 may also comprise a system operation and control mechanism 1012 that provides electronic circuitry and mechanical components to selectively operate valves, manifolds, pumps and other equipment included in the reaction system 1000. Such circuitry and components operate to introduce precursors, purge gases from the respective precursor sources 1004, 1006, 1008, 1009, and purge gas source 1010. The system operation and control mechanism 1012 also controls timing of gas pulse sequences, temperature of the substrate and reaction chamber, and pressure of the reaction chamber and various other operations necessary to provide proper operation of the reaction system 1000. The operation and control mechanism 1012 can include control software and electrically or pneumatically controlled valves to control flow of precursors, reactants, and purge gases into and out of the reaction chamber 1002. The control system can include modules such as a software or hardware component, e.g., a FPGA or ASIC, which performs certain tasks. A module can advantageously be configured to reside on the addressable storage medium of the control system and be configured to execute one or more processes.

Those of skill in the relevant arts appreciate that other configurations of the present reaction system are possible, including a different number and kind of precursor reactant sources and purge gas sources. Further, such persons will also appreciate that there are many arrangements of valves, conduits, precursor sources, purge gas sources that may be used to accomplish the goal of selectively feeding gases into reaction chamber 1002. Further, as a schematic representation of a reaction system, many components have been omitted for simplicity of illustration, and such components may include, for example, various valves, manifolds, purifiers, heaters, containers, vents, and/or bypasses.

The example embodiments of the disclosure described above do not limit the scope of the invention, since these embodiments are merely examples of the embodiments of the invention, which is defined by the appended claims and their legal equivalents. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the disclosure, in addition to those shown and described herein, such as alternative useful combination of the elements described, may become apparent to those skilled in the art from the description. Such modifications and embodiments are also intended to fall within the scope of the appended claims. 

What is claimed is:
 1. A method for forming a rhenium-containing film on a substrate by a cyclical deposition process, the method comprising: contacting the substrate with a first vapor phase reactant comprising a rhenium oxyhalide precursor, an alkyl rhenium oxide precursor, a cyclopentadienyl based rhenium precursor, or a rhenium carbonyl halide precursor; and contacting the substrate with a second vapor phase reactant, wherein the rhenium-containing film comprises a rhenium boron carbide.
 2. The method of claim 1, wherein the second vapor phase reactant comprises at least one of an oxygen containing precursor, a boron containing precursor, a sulfur containing precursor, and a hydrogen containing precursor.
 3. The method of claim 1, further comprising forming a conductive capping layer over a surface of the rhenium-containing film.
 4. The method of claim 3, wherein the conductive capping layer comprises at least one of a titanium nitride, a rhenium boride, a rhenium carbide, a rhenium phosphide, a rhenium nitride, a tantalum nitride, tantalum, a tungsten carbide, molybdenum, or a niobium boride.
 5. The method of claim 1, wherein the alkyl rhenium oxide precursor comprises methyl rhenium trioxide (CH₃ReO₃).
 6. The method of claim 1, wherein the cyclopentadienyl based rhenium precursor comprises at least one of a cyclopentadienyl rhenium hydride and a cyclopentadienyl rhenium carbonyl.
 7. The method of claim 1, wherein the first vapor phase reactant comprises ReCl[CO]₅.
 8. The method of claim 1, wherein the second vapor phase reactant comprises at least one of hydrogen sulfide (H₂S), sulfur dioxide (SO₂), carbon disulfide (CS₂), dimethyl sulfide (C₂H₆S), methanethiol (CH₃SH), and dialkyl disulfides.
 9. The method of claim 1, wherein second vapor phase reactant comprises at least one of hydrogen sulfide (H₂S), molecular hydrogen (H₂), atomic hydrogen (H), a hydrogen based plasma, hydrazine (N₂H₄), forming gas (H₂+N₂), ammonia (NH₃), and an ammonia-hydrogen (NH₃—H₂) mixture.
 10. The method of claim 1, wherein the cyclical deposition process comprises an atomic layer deposition (ALD) process.
 11. The method of claim 1, wherein the cyclical deposition process comprises a cyclical chemical vapor deposition (CCVD) process.
 12. A semiconductor device structure comprising a rhenium-containing film formed by the method of claim
 1. 13. A reaction system configured to perform the method of claim
 1. 14. A method for forming a rhenium-containing film on a substrate by a cyclical deposition process, the method comprising: contacting the substrate with a first vapor phase reactant comprising a rhenium oxyhalide precursor, an alkyl rhenium oxide precursor, or a cyclopentadienyl based rhenium precursor; and contacting the substrate with a second vapor phase reactant, wherein the rhenium-containing film comprises, sulfur, carbon, nitrogen, phosphorus, or a combination thereof, and wherein the rhenium-containing film comprises a rhenium diboride, a dirhenium triboride, or a rhenium boride.
 15. A method for forming a rhenium-containing film on a substrate by a cyclical deposition process, the method comprising: contacting the substrate with a first vapor phase reactant comprising a rhenium oxyhalide precursor, an alkyl rhenium oxide precursor, or a cyclopentadienyl based rhenium precursor; and contacting the substrate with a second vapor phase reactant, wherein the rhenium-containing film comprises at least one of a rhenium boride film or rhenium boron carbide.
 16. The method of claim 15, wherein the second vapor phase reactant comprises at least one of an oxygen containing precursor, a boron containing precursor, a sulfur containing precursor, and a hydrogen containing precursor.
 17. The method of claim 15, wherein the second vapor phase reactant comprises at least one of hydrogen sulfide (H₂S), sulfur dioxide (SO₂), carbon disulfide (CS₂), dimethyl sulfide (C₂H₆S), methanethiol (CH₃SH), and dialkyl disulfides. 